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Arduino Mail Notifier 

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Arduino Mail Notifier 

Written By: Riley Porter 




Arduino microcontroller (2) 

Wire cutter/stripper (1) 


RF Link Transmitter (1) 


Mini breadboard (2) 


10K Resistor M) 


Photoresistor (1) 


Battery holder. 4xAA m 


Breadboard Wire (1) 


RF Link Receiver (1) 


Many inventions/hacks often arise out of the need to solve a problem. The Arduino mailer 
notifier project was no exception. My workshop is in my backyard. During the day, I am far 
away from my mailbox. Using two Arduinos, some cheap RF modules, and a light sensor, I 
was able to create a solution that alerts me when my mail has arrived. In this project, I will 
show you how I did it. 

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Arduino Mail Notifier 

Step 1 — Putting Together the Circuits. 

• Wire up the two Arduino boards 
as shown in this diagram 

• On the receiver there are 
multiple places for GND and 
VCC. Connect all of the GND's 
together and the VCC's together. 

Step 2 

• Build your antennas (2x) 

• Cut roughly 12" of breadboarding 

• Strip 1/4" off of one side of each 

• Tightly wrap one wire around a 

• Remove both wires and insert 
them into the Ant port on each 


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Arduino Mail Notifier 

Step 3 

• Copy and pase the code from the URLs below into two different Arduino Sketches. Be sure 
to load the Receiver code on to the Receiver Arduino ciruit and vice versa. 

• Receiver Code: https://github.eom/ril3y/Make-Projects/r... 

• Sender Code: https://github.eom/ril3y/Make-Projects/r... 

Step 4 

Tweak the Sender Settings. 

• The sender sketch works as follows. It continues to check to see if the LDR reading 
(light sensor) is above the THRESHOLD value. See the image attached. I placed a red 
square box around the THRESHOLD var. Since each mailbox's ambient light will vary 
from place to place I created this THRESHOLD variable. 

• Inside the Sender sketch is a DEBUG variable. If you set this value to equal 1. then ALL 
light readings will be sent to the receiver. This is a good way to see what your mail box 
registers while the lid is closed. 

• Record your closed lid value and your open lid value. For example: If your open lid was 
300 and your closed lid was 600 then setting your THRESHOLD value to 350 might be a 
good value to try. 

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Arduino Mail Notifier 

Step 5 

Test it all out. 

• Now that your Sender sketch is all tweaked for your mailbox lets see how it works. 

• Place your Sender in the mailbox. 

• Hookup your receiver to your computer. 

• Open your serial terminal window. (See image). 

• Now have someone go open your mail box. 

• If all went well you should have message that says "Got: Your Mail". It should also be 
noted that in the Sender sketch there is a "TIMEOUT" var. This is the number of 
milliseconds that will occur before your Arduino starts looking for mail again. This way 
you do not have to manually reset your mail checker. 

This project was designed to get you used to working with cheap and simple RF modules while 
providing a cool, practical application. There is much room for improvement here. For instance, 
if this were a long-term project, much code optimization would need to be done to have the 
processor "sleep." Also, for alerting purposes, perhaps an LED or some audible alert could be 

In O'Reilly's "Arduino Cookbook," in recipe 14.1 Sending Messages Using Low-Cost Wireless 
Modules, there is much more information about using these RF modules. 

You can get the book here at the Maker Shed . 

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Arduino Mail Notifier 

For another mailbox alert system, check out Matt Richardson's Snail Mail Push Alerts project. 
And for lots more Arduino, take a gander at the Make: Arduino page. 

st generated on 2012-1 1 -02 01 :03:47 AM. 

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